Secondary outcome measure: For the HomVEE review, most self-reported
data, excluding self-reports based on a standardized (normed) instrument.

Mean Difference
and Odds Ratio

For a uniform approach, HomVEE calculates mean differences as the
program group mean minus the comparison group mean. In some studies, authors did
this calculation in the opposite direction.

The odds ratio is the odds of an event occurring in one group divided
by the odds of an event occurring in another group. If the odds of an event occurring
in group A equals 3 and the odds of an event occurring in group B equals 2, the
odds ratio equals 1.5. In other words, there is a 1.5 times greater likelihood the
event will occur in group A than in group B.

Effect Sizes

HomVEE reports author-calculated effect sizes when available, as labeled in the
table. If the author did not report effect sizes, but sufficient information was
available, HomVEE calculated effect sizes.

Statistical Significance

Statistical significance is an indication of the probability that the observed finding
was obtained by chance (when there is not a real relationship in the population).
If the p-value is equal to or less than a predetermined cutoff (in the
HomVEE review, 0.05), then the finding is considered statistically significant or
probably not obtained by chance.